Woolly Mammoth
The Woolly Mammoth was a prehistoric elephant which lived a long time ago. It was large and covered with a shaggy exterior of long dark brown hair .It may have become extinct of climate change or hunting by Cavemen. It had very long,loopy tusks. It was one of the most famous ice age animals. Bodies have been found frozen well-preservedly in ice or in tar pits. They were preyed upon by saber-toothed cats or any other carnivore of the ice age. A mammoth is any species of the extinct genus Mammuthus. These proboscideans are members of Elephantidae, the family of elephants and mammoths, and close relatives of modern elephants. They were often equipped with long curved tusks and, in northern species, a covering of long hair. They lived from the Pliocene Epoch from around 4.8 million into the Pleistocene at about 4,500 years ago. The word mammoth comes from the Russian мамонт mamont , probably in turn from the Vogul (Mansi) language, mang ont, meaning "earth horn". An extinct class of elephants, mammoths belonged to a diverse and widespread group of mammals known as the proboscideans, characterized by long, trunk-like noses. Mammoths first appeared in Africa early in the Pleistocene Epoch (the last 1.6 million years of the Earth’s history) and later migrated to Europe, Siberia, and across to North America. Proboscideans were very widespread. Their fossil remains can be found on every continent except Australia and South America. The genus Mammuthus includes a number of several species, of which the best known is the woolly mammoth. There are also the steppe mammoth, imperial mammoth, dwarf mammoths, columbian mammoth, songhua river mammoth and wrangel islands woolly mammoth. Taxonomy Remains of various extinct elephants were known by Europeans for centuries, but were generally interpreted, based on biblical accounts, as the remains of legendary creatures such as behemoths or giants. It was also theorised that they were remains of modern elephants that had been brought to Europe during the Roman Republic, for example the war elephants of Hannibal the Great and Pyrrhus of Epirus, or animals that had wandered north.2 The first woolly mammoth remains studied by European scientists were examined by Hans Sloane in 1728 and consisted of fossilised teeth and tusks from Siberia. Sloane was the first to recognise that the remains belonged to elephants.3 Sloane turned to another biblical explanation for the presence of elephants in the Arctic, asserting that they had been buried during the Great Flood, and that Siberia had previously been tropical prior to a drastic climate change.4 Others interpreted Sloane's conclusion slightly differently, arguing the flood had carried elephants from the Tropics to the Arctic. Sloane's paper was based on travellers' descriptions and a few scattered bones collected in Siberia and Britain. He discussed the question of whether or not the remains were from elephants, but drew no conclusions.5 In 1738, Johann Philipp Breyne argued that mammoth fossils represented some kind of elephant. He could not explain why a tropical animal would be found in such a cold area as Siberia, and suggested that they might have been transported there by the Great Flood.6 In 1796, French anatomist Georges Cuvier was the first to identify the woolly mammoth remains not as modern elephants transported to the Arctic, but as an entirely new species. He argued this species had gone extinct and no longer existed, a concept that was not widely accepted at the time. Etymology Following Cuvier's identification, Johann Friedrich Blumenbach gave the woolly mammoth its scientific name, Elephas primigenius, in 1799, placing it in the same genus as the Asian elephant. This name means "the firstborn elephant". Henry Fairfield Osborn chose a molar from Blumenbach's collection as the lectotype specimen for the species in 1942, since holotype designation was not practised in Blumenbach's time.8 In 1828 Joshua Brookes recognised the species was distinct enough to warrant a new genus, and reclassified it as Mammuthus primigenius.9 It is unclear where and how the word "mammoth" originated. It may be a version of mehemot, the Arabic version of the biblical word "behemoth". Another possible origin is Estonian, where maa means earth, and mutt means mole. The word was first used in Europe during the early 17th century, when referring to maimanto tusks discovered in Siberia.10 Thomas Jefferson, who had a keen interest in palaeontology, is partially responsible for transforming the word mammoth from a noun describing the prehistoric elephant to an adjective describing anything of surprisingly large size. The first recorded use of the word as an adjective was in a description of a wheel of cheese (the "Cheshire Mammoth Cheese") given to Jefferson in 1802. Evolution The earliest known proboscideans, the clade which contains elephants, existed about 55 million years ago around the Tethys Sea. The closest known relatives of the Proboscidea are the sirenians and the hyraxes. The family Elephantidae existed six million years ago in Africa and includes the modern elephants and the mammoths. Among many now extinct clades, the mastodon is only a distant relative of the mammoths, and part of the separate Mammutidae family, which diverged 25 million years before the mammoths evolved.12 The following cladogram shows the placement of the genus Mammuthus among other proboscideans, based on hyoid characteristics: }} }} }} }} }} }} In 2005, researchers assembled a complete mitochondrial genome profile of the woolly mammoth, which allowed them to trace the close evolutionary relationship between mammoths and Asian elephants, Elephas maximus.14 African elephants, Loxodonta africana, branched away from this clade around 6 million years ago, close to the time of the similar split between chimpanzees and humans. Before the publication of the Neanderthal genome, many researchers expected the first fully sequenced nuclear genome of an extinct species would be that of the mammoth.15 A 2010 study confirmed these relationships, and suggested the mammoth and Asian elephant lineages diverged 5.8–7.8 million years ago, while African elephants diverged from an earlier common ancestor 6.6–8.8 million years ago.16 In 2008, much of the woolly mammoth's chromosomal DNA was mapped. The analysis showed that the woolly mammoth and the African elephant are 98.55% to 99.4% identical.17 The team mapped the woolly mammoth's nuclear genome sequence by extracting DNA from the hair follicles of both a 20,000-year-old mammoth retrieved from permafrost, and another that died 60,000 years ago.18 In 2012, proteins were confidently identified for the first time, collected from a 43.000 old woolly mammoth. Since many remains of each species of mammoth are known from several localities, it is possible to reconstruct the evolutionary history of the genus through morphological studies. Mammoth species can be identified from the number of enamel ridges on their molars; primitive species had few ridges, and the number increased gradually as new species evolved and replaced the preceding ones. The crowns of the teeth lengthened and the skulls became taller to accommodate this. At the same time, the skulls became shorter from front to back to minimise the weight.20 These adaptations were acquired gradually as mammoths turned to more abrasive food items. The first known members of the genus Mammuthus are the African species M. subplanifrons from the Pliocene, and M. africanavus from the Pleistocene. The former is thought to be the ancestor of later forms. Mammoths entered Europe around 3 million years ago. The earliest type known from there has been named M. rumanus, which spread across Europe and China. Only its molars are known, which show that it had 8–10 enamel ridges. A population evolved 12–14 ridges, splitting off from and replacing the earlier type, becoming M. meridionalis. In turn, this species was replaced by the steppe mammoth, M. trogontherii, with 18–20 ridges, which evolved in eastern Asia c. 1 million years ago. Mammoths derived from M. trogontherii evolved molars with 26 ridges 200,000 years ago in Siberia and became the woolly mammoth, M. primigenius.20 The Columbian mammoth, M. columbi, evolved from a population of M. trogontherii that had entered North America. A 2011 genetic study showed that two examined specimens of the Columbian mammoth were grouped within a subclade of woolly mammoths. This suggests that the two populations interbred and produced fertile offspring. A North American form known as M. jeffersonii may be a hybrid between the two species.22 Individuals and populations showing transitional morphologies between each of the mammoth species are known, and primitive and derived species coexisted as well until the former disappeared. The different species and their intermediate forms can therefore be termed "chronospecies". Many intermediate subspecies have also been proposed, but their validity is uncertain; depending on author, they are either considered primitive forms of an advanced species or advanced forms of a primitive species.20 Regional and intermediate subspecies such as M. p. primigenius, M. p. jatzkovi, M. p. sibiricus, and M. p. fraasi have been proposed.23 The St. Paul Island and Wrangel Island populations were described as dwarf varieties, much smaller than the mainland woolly mammoth; the Wrangel Island population was also proposed to be a new subspecies, M. p. vrangeliensis.2425 The Wrangel mammoths were isolated for 5000 years, but only experienced a slight loss of genetic variation. Description Most mammoths became extinct around 10,000 years ago, surviving on Siberia’s Wrangel Island longer than anywhere else on earth. Radiocarbon dating indicates that a dwarf population existed there until between 7000 and 3,700 years ago. Paleobiology In popular culture Category:Pleistocene proboscideans Category:Extinct animals of North America Category:Holocene Category:Extinct animals of Europe Category:Prehistoric mammals of Asia